U.S. patent application number 12/484427 was filed with the patent office on 2009-12-24 for liquid ejection head and method of manufacturing the same.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Takuya Hatsui, Satoshi Ibe, Hirokazu Komuro, Sadayoshi Sakuma.
Application Number | 20090315953 12/484427 |
Document ID | / |
Family ID | 41430795 |
Filed Date | 2009-12-24 |
United States Patent
Application |
20090315953 |
Kind Code |
A1 |
Ibe; Satoshi ; et
al. |
December 24, 2009 |
LIQUID EJECTION HEAD AND METHOD OF MANUFACTURING THE SAME
Abstract
Provided is a method of manufacturing a liquid ejection head
having an element which generates energy utilized for ejecting
liquid and an electrode layer electrically connected the element.
The method includes the steps of: providing an electrode layer on a
substrate, a width of one portion of the electrode layer being
smaller than that of another portion near the one portion;
providing a resist layer on a part of the electrode layer by any
one of a screen printing method and a dispense method in such a
manner that an end of the resist layer is positioned at the one
portion; providing another layer on another part excluding the part
of the electrode layer by utilizing the resist layer as a mask; and
removing the resist layer.
Inventors: |
Ibe; Satoshi; (Yokohama-shi,
JP) ; Komuro; Hirokazu; (Yokohama-shi, JP) ;
Hatsui; Takuya; (Tokyo, JP) ; Sakuma; Sadayoshi;
(Yokohama-shi, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
1290 Avenue of the Americas
NEW YORK
NY
10104-3800
US
|
Assignee: |
CANON KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
41430795 |
Appl. No.: |
12/484427 |
Filed: |
June 15, 2009 |
Current U.S.
Class: |
347/63 ;
29/890.1 |
Current CPC
Class: |
B41J 2/1603 20130101;
B41J 2/1643 20130101; Y10T 29/49083 20150115; Y10T 29/49147
20150115; Y10T 29/49155 20150115; B41J 2/1646 20130101; Y10T
29/49401 20150115; B41J 2/14129 20130101; B41J 2/1631 20130101 |
Class at
Publication: |
347/63 ;
29/890.1 |
International
Class: |
B41J 2/05 20060101
B41J002/05; B21D 53/76 20060101 B21D053/76 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 18, 2008 |
JP |
2008-159657 |
Claims
1. A method of manufacturing a liquid ejection head having an
element which generates energy utilized for ejecting liquid and an
electrode layer electrically connected the element, the method
comprising the steps of: providing an electrode layer on a
substrate, a width of one portion of the electrode layer being
smaller than that of another portion near the one portion;
providing a resist layer on a part of the electrode layer by a
screen printing method or a dispense method in such a manner that
an end of the resist layer is positioned at the one portion;
providing another layer on another part excluding the part of the
electrode layer by utilizing the resist layer as a mask; and
removing the resist layer.
2. A method as claimed in claim 1, wherein the electrode layer
contains gold, and the other layer contains nickel.
3. A method as claimed in claim 1, wherein the electrode layer is
substantially formed of gold only, and the other layer is
substantially formed of nickel only.
4. A method as claimed in claim 1, wherein the other layer is
formed by plating.
5. A liquid ejection head comprising: a substrate provided with an
element which generates energy utilized for ejecting liquid; an
electrode layer provided on the substrate and electrically
connected the element; and a metal-containing layer provided on a
part of the electrode layer, wherein a portion of the electrode
layer on which an end of the metal-containing layer is provided has
a smaller width than another portion near the portion.
6. A liquid ejection head as claimed in claim 5, wherein the
electrode layer contains gold.
7. A liquid ejection head as claimed in claim 5, wherein the
metal-containing layer contains nickel.
8. A liquid ejection head as claimed in claim 5, wherein a wall
member having a wall for liquid passage is provided on the
metal-containing layer, the wall member being formed of a hardened
epoxy resin.
9. A liquid ejection head as claimed in claim 8, wherein a face of
the wall member facing the substrate has an adhesion improvement
layer made of a polyetheramide resin.
10. A liquid ejection head as claimed in claim 5, wherein a portion
of the metal-containing layer on the portion of the electrode layer
has a smaller width than another portion of the metal-containing
layer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a liquid ejection head that
employs a scheme in which liquid is ejected by using energy, a
method of manufacturing the liquid ejection head.
[0003] 2. Description of the Related Art
[0004] Through similar processes to that for semiconductor
manufacturing, a substrate for a liquid ejection head is
manufactured by forming, on the same substrate, multiple heaters
for heating liquid to generate bubbles when being energized, lines
for providing electrical connection to the heaters, and the like.
Then, a liquid ejection head is constructed in a way that a member
(nozzle formation member) forming ejection openings and liquid
passages is provided on the substrate. Here, the ejection openings
are provided corresponding to the heaters and are used to eject ink
therefrom. Meanwhile, the liquid passages are formed to communicate
with the corresponding ejection openings, respectively.
[0005] One method of manufacturing the liquid ejection head (see
Japanese Patent Laid-Open No. H06-286149 (1994) includes the
following steps: [0006] (1) forming a pattern to form the liquid
passages on the substrate with a dissolvable resin; [0007] (2)
applying a coating resin containing an epoxy resin being solid at
ordinary temperature; [0008] (3) forming openings to be the
ejection openings in the coated resin; and [0009] (4) dissolving
the dissolvable resin layer.
[0010] Further, there has been proposed a liquid ejection head and
a method of manufacturing a liquid ejection head in which a layer
made of a polyetheramide resin (called an adhesion improvement
layer below) is interposed between the substrate and the nozzle
formation member in order to improve the adhesion between them (see
Japanese Patent Laid-Open No. H11-348290 (1999)).
[0011] FIG. 8A is a schematic perspective view showing a general
example of the configuration of the liquid ejection head, and FIG.
8B is a cross-sectional view taken along the VIII(b)-VIII(b) line
in FIG. 8A. A substrate 1110 made of Si or the like is provided
with an ink supply opening 1202 being a slot-like through-hole, and
ink is introduced into this ink supply opening 1202. Further, two
arrays of heaters 1214 are formed, one on each side of the ink
supply port 1202. Electrode portions 202 are formed along a side of
the substrate 1110 in a direction perpendicular to an arrangement
direction of the heaters 1214. The electrode portions 202 are
formed to provide external electric connection to the heaters 1214
or to a logic circuit for selectively energizing the heaters 1214,
and are connected to the heaters 1214 or to the logic circuit via
lines 201. Then, a nozzle formation member 203 is disposed on the
substrate 1110 in a contacting manner. The nozzle formation member
203 is provided with liquid passages 1106 and ejection openings
1107 from each of which ink is ejected toward a printing medium
with the action of thermal energy.
[0012] To reduce a line resistance value, the following technique
has been proposed. Specifically, the lines 201 and the electrode
portions 202 are simultaneously formed as a gold (Au) layer by
plating (see Japanese Patent Laid-Open No. 2005-199701). Gold has
excellent properties as a line material because of its low electric
resistance, high chemical stability, high electromigration
characteristics, and the like. Particularly, gold is excellent as a
line material of a substrate for a liquid ejection head because the
lines constantly exist very close to the ink being liquid and are
used to energize the heaters to raise their temperature
instantly.
[0013] Regarding the above lines, there is a need to form an upper
layer on the lines in cases as follows.
[0014] In the configuration of the liquid ejection head described
in Japanese Patent Laid-Open No. H06-286149 (1994) or No.
H11-348290 (1999), a surface of metal such as the lines existing on
the substrate adheres to an organic resin constituting the nozzle
formation member or the adhesion improvement layer. This adhesion
is thought to be brought by a physical anchor effect of the organic
resin entering the dips in the surface of the metal, and also by
chemical bond, hydrogen bond, or the like through the OH groups
existing on the surface of the metal.
[0015] However, depending on the line material, the following
problems may arise. For example, in a case where lines are formed
of gold, as gold is a stable noble metal and has a few OH groups on
its surface, gold has poor bonding power with an organic resin. In
addition, on a liquid ejection head substrate, the organic resin
film swells because ink constantly exists near the ejection
openings. Particularly, in a liquid ejection head substrate with
heaters, heat generated by the heaters causes the organic resin and
the substrate to expand to different degrees. As a result, the
liquid ejection head substrate with heaters undergoes internal
stress caused by the difference in thermal expansion between the
substrate and the organic resin, in addition to the swelling of the
organic resin film. This stress could possibly cause separation of
the nozzle formation member from the Au layer, originating from and
around parts having poor adhesion with the organic resin. To avoid
such a separation, an upper layer may be required on the lines.
Besides this, an upper layer may be formed various objectives. For
example, an upper layer may be required on a desired portion of
lines in order to improve the reliability by protecting a line
surface and the like from damages.
[0016] A possible way to form the upper layer is to form and then
pattern a film of an insulating material such as SiN or SiC by
using a vacuum film forming device or the like, on and the vicinity
of the lines. However, since the vacuum film forming device and a
patterning device are expensive, the above way will result in
increased costs for manufacturing the substrate, and in turn, the
liquid ejection head. In addition, there is concern that the
manufacturing process of the substrate becomes complex. Moreover,
the above way may possibly lower the energy efficiency in a liquid
ejection head that employs the scheme in which liquid is ejected by
using energy generated by the heaters.
SUMMARY OF THE INVENTION
[0017] The present invention has been made in consideration of the
above problems. An objective of the present invention is to provide
a method for obtaining a liquid ejection head with high reliability
by providing a proper laminating state of layers disposed as upper
layers on lines on the substrate in a simple way.
[0018] In an aspect of the present invention, there is provided a
method of manufacturing a liquid ejection head having an element
which generates energy utilized for ejecting liquid and an
electrode layer electrically connected the element, the method
comprising the steps of: [0019] providing an electrode layer on a
substrate, a width of one portion of the electrode layer being
smaller than that of another portion near the one portion; [0020]
providing a resist layer on a part of the electrode layer by a
screen printing method or a dispense method in such a manner that
an end of the resist layer is positioned at the one portion; [0021]
providing another layer on another part excluding the part of the
electrode layer by utilizing the resist layer as a mask; and [0022]
removing the resist layer.
[0023] In another aspect of the present invention, there is
provided a liquid ejection head comprising: [0024] a substrate
provided with an element which generates energy utilized for
ejecting liquid; [0025] an electrode layer provided on the
substrate and electrically connected the element; and [0026] a
metal-containing layer provided on a part of the electrode layer,
wherein [0027] a portion of the electrode layer on which an end of
the metal-containing layer is provided has a smaller width than
another portion near the portion.
[0028] According to the present invention, upper layers are allowed
to be properly laminated on lines in a simple manner. As a result,
the reliability of the liquid ejection head can be improved without
complicating the manufacturing process.
[0029] Further features of the present invention will become
apparent from the following description of exemplary embodiments
(with reference to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a schematic perspective view showing a
configuration example of a substrate for a liquid ejection head
according to an embodiment of the present invention;
[0031] FIGS. 2A to 2E are schematic plan views showing various
configuration examples of a connecting portion of an electrode
portion and a line portion on a substrate shown in FIG. 1;
[0032] FIG. 3 is a schematic plan view illustrating a connection
state between common lines and individual heater lines on the
substrate of FIG. 1;
[0033] FIG. 4 is a schematic cross-sectional view taken along the
IV-IV line in FIG. 1, and shows the layer structure of the
electrode portion and the line portion;
[0034] FIGS. 5A to 5H are diagrams illustrating the steps for
obtaining the structure shown in FIG. 4;
[0035] FIGS. 6A, 6B, 6C, 6D, and GE are plan views of FIGS. 5C, 5D,
5E, 5F, and FIG. 4, respectively;
[0036] FIG. 7 is a schematic cross-sectional view showing a state
in which an organic resin layer to be a nozzle formation member is
formed on the substrate of FIG. 4; and
[0037] FIG. 8A is a schematic perspective view showing a general
example of the configuration of the liquid ejection head, and FIG.
8B is a cross-sectional view taken along the VIII(b)-VIII(b) line
in FIG. 8A.
DESCRIPTION OF THE EMBODIMENTS
[0038] The present invention will be described in detail below with
reference to the drawings.
[0039] FIG. 1 is a schematic perspective view showing a
configuration example of a substrate for a liquid ejection head
according to an embodiment of the present invention. Parts
configured similarly to those in FIGS. 8A and 8B are denoted by the
same corresponding reference numerals.
[0040] In a substrate 1110 of the present embodiment, electrode
portions 140 and line portions 141 are formed on the base plate 101
made of Si or the like, and are connected at the surface of the
base plate 101. These portions can be simultaneously formed by
forming a layer (Au layer) 130 containing gold as a main component,
by plating. In the present embodiment, Au is used as a plating
material. Instead, any other low-resistant metallic material
containing Cu, Ag, or Pd as a main component can also be used. The
electrode portions 140 are connected with a flexible printed
circuit board using, for example, a tape member for tape-automated
bonding (TAB), and are thereby allowed to transmit and receive
electrical signals to and from a main body of a liquid-ejection
type of printing apparatus device (not shown). Formed on and the
vicinity of surfaces of the line potions 141 is a layer 112 for
providing adhesion with an adhesion improvement layer made of an
organic resin such as a polyetheramide resin, or the nozzle
formation member made of a resin, or the like.
[0041] The layer 112 is formed so that its end surface is
positioned at a connecting portion 142 between each of the
electrode portions 140 and of the line portions 141. The connecting
portion 142 is formed so that its width in a direction traversing a
longitudinal direction is smaller than those of the electrode
portion 140 and the line portion 141. This is for blocking a mask
material 113 from flowing into the line portion 141 when the mask
material 113 is applied to the electrode portion 140 before removal
of a photoresist 122. The viscosity of the mask material 113 may be
selected depending on the width of the connecting portion 142. Such
formation of the layer 112 has two meanings. Firstly, the layer 112
plays a role of improving the adhesion between the gold lines and
an organic resinous member (nozzle formation member) formed above
it. Certain improvement of the adhesion with the organic resinous
member can be observed visually if an end part of the layer 112 is
sticking out of the organic resinous member. Secondly, by being
formed to have a small width, the connecting portion 142 can serve
as a characteristic mark (characteristic part) for recognizing the
area to which a flexible printed circuit member for supplying power
to the liquid ejection head is to be connected.
[0042] FIGS. 2A to 2D show various shape types of the connecting
portion 142. As shown in these drawings, the shape of the
connecting portion 142 can be determined appropriately as long as
it can serve as a visual observation mark used in: recognizing the
position of the end part of the layer 112; connecting the electric
circuit board; and forming ejection openings. Further, as shown in
FIG. 2E, as long as the connecting portion 142 can serve as the
visual observation mark, it may have substantially the same width
as the electrode portion 140 and the line portion 141 and then have
a part that can be a characteristic mark (an opening in FIG.
2E).
[0043] For example, the line portion 141 can serve as a common
power supply line or a common ground line that are connected to the
multiple heaters 1214 to supply power to them. Via through holes,
the line portion 141 may be connected to lines which are formed of
Al or the like and are connected to the corresponding heaters 1214
individually.
[0044] FIG. 3 is a schematic plan view showing an example of the
configuration of and around the heaters 1214 on the substrate 1110.
The multiple heaters 1214 are formed on the base plate 101 onto
which a drive circuit including driving elements is built in
advance. The driving element is formed of a semiconductor element
such as a switching transistor, and selectively drives the heater
1214. The heaters 1214 are formed as follows. First, a heating
resistor layer is formed on the base plate 101. Further, an
electrode layer is laminated, from which lines (heater lines) 1103
for the heaters 1214 are formed. Then, a desired pattern is formed
by continuously etching the layers. Moreover, the electrode layer
is removed in part to expose the heating resistor layer
underneath.
[0045] For example, one end of each of the heaters 1214 can be
connected to the line portion 141 serving as the common power
supply line, via one part 1103A of the heater line 1103 and then a
through-hole part 1208. The other end of the heater 1214 is
connected to the drive circuit formed in the layer underneath, via
another part 1103B of the heater line 1103 and then, for example, a
through-hole part 1209. The other end of the heater 1214 can be
then connected to a line portion serving as the common ground
line.
[0046] FIG. 4 is a schematic cross-sectional view taken along the
IV-IV line in FIG. 1.
[0047] In FIG. 4, reference numeral 102 represents a heat
accumulating layer made of SiO.sub.2 formed on a silicon (Si) base
plate 101. Reference numeral 103 represents a heating resistor
layer from which the heaters 1214 are formed. Reference numeral 104
represents an Al line layer from which the heater lines 1103
connected with the heaters 1214 individually are formed. Reference
numeral 105 represents a protection layer covering these layers,
and reference numeral 110 represents a diffusion prevention
layer.
[0048] Reference numeral 111 is a layer (called a plating
underlayer below) used as an electrode which is used when the
electrode portion 140 and the line portion 141 are simultaneously
formed with the Au layer 130 by electrolytic plating. The plating
underlayer 111 may be an Au layer formed on the diffusion
prevention layer 110. The plating underlayer 111 is also used when
the metallic layer 112 is formed on the Au layer 130 by plating to
provide adhesion with the organic resinous member. A material used
for the layer 112 is an inorganic material having more OH groups
than gold, in other words, a material providing higher adhesion
with an organic resin than gold. In the present embodiment, nickel
(Ni) is used. In this case, the layer 112 may be a layer which
substantially contains Ni only, or may be made of an alloy
containing Ni. In addition, reference numeral 150 is an adhesion
improvement layer formed on the metallic layer 112 to improve
adhesion with the nozzle formation member 203. The adhesion
improvement layer 150 can be formed by patterning of a
polyetheramide resin.
[0049] Using FIGS. 5A to 5H, a description will be given of a
method of manufacturing the substrate shown in FIG. 4.
[0050] Firstly, as shown in FIG. 5A, the heat accumulation layer
102 is formed in an about 1 .mu.m thickness on the Si base plate
101 by thermal oxidation. Further, the heating resistor layer 103,
the Al line layer 104, and the protection layer 105 are formed by a
vacuum film forming method or the like. Then, a through-hole 106 is
formed by photolithography patterning to provide electrical
conduction between the metallic layer (Au layer) 130 to be the line
portion 141 and the Al line layer 104 to be the individual heater
lines 1103. Note that, a drive circuit including semiconductor
elements, such as switching transistors for selectively driving the
heaters 1214, can be built in the base plate 101 in advance.
[0051] Next, as shown in FIG. 5B, the diffusion prevention layer
110 and the plating underlayer 111 are formed on the entire surface
by using a vacuum film forming device or the like. Specifically,
the diffusion prevention layer 110, which is made for example of
titanium tungsten being a high-melting-point metal material, is
formed in an about 200 nm thickness, and the gold plating
underlayer 111 is formed in an about 50 nm thickness.
[0052] Next, as shown in FIG. 5C, the photoresist 122 is applied,
exposed, and developed using photolithographic method. Thereby, an
opening is defined in an area for forming the metallic layer 130.
Here, the photoresist 122 is applied to have a thickness larger the
thickness (height) of the metallic layer 130 to be formed on the
substrate. In the present embodiment, the photoresist 122 is formed
to have a thickness of 6 .mu.m, whereas the film thickness of the
gold plating is about 5 .mu.m. FIG. CA is a plan view of FIG. 5C.
As shown in FIG. 6A, the photoresist 122 is provided in such a
manner as to surround the part in which the metallic layer 130 is
to be formed. The connecting portion 142 is formed so that its
width in the direction traversing the longitudinal direction is
smaller than those of the electrode portion 140 and the line
portion 141.
[0053] After that, as shown in FIG. 5D, the metallic layer 130 is
formed by electrolytic plating. This is carried out for example by
immersing the substrate in an electrolytic solution containing gold
sulfite, applying a predetermined current to the plating underlayer
111, and depositing gold on a predetermined portion. FIG. 6B is a
plan view of FIG. 5D.
[0054] Next, as shown in FIG. 5E, to and the vicinity of a portion
on the layer 130 to be the electrode portion 140, the mask material
113 having the same material as the photoresist 122 is printed by
using a screen printing method or is applied by using a dispense
method in which a material is ejected from a nozzle. Then, the mask
material 113 is hardened at a predetermined temperature. When the
screen printing method is used, the mask material 113 can be
printed at high speed. Specifically, in the screen printing method,
the mask material 113 having the same material as the photoresist
122 is printed by: preparing a printing plate in which a part
corresponding to the electrode portion 140 is opened in advance;
adjusting the position of the printing plate relative to the
substrate; and sliding a squeegee positioned above them onto the
printing plate. In the dispense method, on the other hand, the mask
material 113 contained in a syringe is applied to a target part in
a predetermined amount while forming lines. Accordingly, a
production take time is lower than the case of using the screen
printing method. However, the dispense method has the following
advantages: the solvent of the material does not volatilize in the
atmosphere; the viscosity or the like of the material does not
change; and there is small variation in the line widths.
[0055] The mask material 113 is applied to the inside of the
portion defined by the photoresist 122, along a step formed by the
metallic layer 130 and the photoresist 122, the step having about 1
.mu.m height. FIG. 6C is a plan view of FIG. 5E. The mask material
113 can be applied so that its end is positioned at the connecting
portion 142, through adjustment of the viscosity and ejection
amount of the mask material 113. Here, the connecting portion 142
is a portion where the photoresist 122 is narrowed. Accordingly, if
the wettability of the photoresist 122 is properly designed, the
mask material 113 can be prevented from spreading toward the inside
of the portion defined by the photoresist 122, by positioning the
end of the mask material 113 at the narrowed portion of the
photoresist 122. As a result, the mask material 113 can be applied
to a desired location.
[0056] Next, as shown in FIG. 5F, the layer 112 is formed by
electrolytic plating. This is carried out for example by immersing
the substrate in an electrolytic solution containing nickel
sulfamate, applying a predetermined current to the plating
underlayer 111, and depositing nickel of an about 200 nm thickness
on a predetermined portion, that is, a portion on the Au layer 130
which is to be in contact with the adhesion improvement layer 150.
FIG. 6D is a plan view of FIG. 5F.
[0057] Next, the photoresist 122 and the mask material 113 are
removed by immersing the substrate in a predetermined stripping
solution for a predetermined length of time. Thereby, as shown in
FIG. 5G, the metallic layer (Au layer) 130 is exposed at a portion
corresponding to the electrode portion 140, and the plating
underlayer 111 is exposed at an end of the substrate.
[0058] Next, an unneeded part of the plating underlayer 111 exposed
at the end of the substrate is removed by immersion in a solution
containing nitrogen organic compounds, iodide, and potassium
iodide, for a predetermined length of time. Thereby, as shown in
FIG. 5H, the diffusion prevention layer 110 is exposed.
[0059] Further, an unneeded part of the diffusion prevention layer
110 is removed by immersion in hydrogen peroxide solution for a
predetermined length of time. Thereafter, the adhesion improvement
layer 150 is formed. The adhesion improvement layer 150 improves
the adhesion with the nozzle formation member 203, and also gives
the line area insulating properties The adhesion improvement layer
150 can be formed by photolithography patterning of a
polyetheramide resin.
[0060] The substrate shown in FIG. 4 can be obtained by the steps
described above. FIG. 6E is a plan view of FIG. 4.
[0061] Then, as shown in FIG. 7, an organic resin layer 151 to be
the nozzle formation member is applied to the adhesion improvement
layer 150 to a predetermined thickness by a spin coat method. The
organic resin layer 151 is then subjected to exposure, development,
and the like by photolithography, and the nozzle formation member
203 is thus formed. For example, the nozzle formation member 203
can be formed using a technique as shown in Japanese Patent
Laid-Open No. H06-286149 (1994). To be more specific, the nozzle
formation member 203 can be disposed by performing the steps of:
[0062] (1) forming a liquid-passage pattern on the substrate
manufactured by the above-described steps, with a dissolvable
resin; [0063] (2) applying a coating resin containing an epoxy
resin being solid at ordinary temperature; [0064] (3) forming
openings to be the ejection openings in the coating resin; and
[0065] (4) dissolving the dissolvable resin layer.
[0066] That is, the nozzle formation member is formed of a hardened
epoxy resin, and includes a wall member having walls for the liquid
passages communicated with the ejection openings.
[0067] Through the steps described above, the liquid ejection head
as shown in 8A can be obtained. The liquid ejection head of the
present invention includes the substrate having a characteristic
structure as shown in FIG. 4.
[0068] More precisely, the substrate of the present embodiment is
formed such that plating of a metal (Ni) is applied on and the
vicinity of the line portion 141. Here, the metal is an inorganic
material having more OH groups than gold. Thereby, adhesion with
the adhesion improvement layer 150, and in turn, with the nozzle
formation member 203 can be improved. This prevents the nozzle
formation member 203 from being separated from the substrate, and
thus can improve the reliability of the liquid ejection head.
[0069] In addition, by properly applying the mask material 113 in
prior to the formation of the metallic layer (Ni layer) 112, Ni
layer 112 is not formed on the electrode portion 140. This allows
gold to be exposed on that portion after completion of the
substrate, and thus makes it possible to reliably maintain the
electric connection to the outside.
[0070] As a result, a highly-reliable substrate for liquid ejection
head can be obtained through a proper lamination of the layers on
the electric lines for supplying power to the ejection energy
generating element being a metallic layer formed by plating.
[0071] Note that the layer disposed on the Au layer, which
constitutes the line portion 141, to improve the adhesion with the
organic resin can be made of any material as long as the layer can
serve functions described above and has enough chemical stability
against liquid such as ink when coming in contact therewith. In
other words, the layer may be formed of Ni only, or may be formed
of a material containing Ni as a main component.
[0072] The Ni layer used for the metallic layer 112 may be formed
by sputtering, other than plating. The layer containing Ni as the
main component means a Ni layer containing minute impurities
incorporated when forming the metallic layer 112 by plating or
sputtering.
[0073] In the structure described in the above example, the
adhesion improvement layer made of organic resin serving also as an
insulating layer is interposed between the substrate and the nozzle
formation member. However, such an adhesion improvement layer does
not necessarily have to be interposed when a good adhesion is
achieved between the nozzle formation member made of an organic
resin and the layer made of an inorganic material according to the
present invention, and when, or to where, insulating properties do
not need to be considered.
[0074] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0075] This application claims the benefit of Japanese Patent
Application No. 2008-159657, filed Jun. 18, 2008, which is hereby
incorporated by reference herein in its entirety.
* * * * *